Drivers who spoke with the Sunshine Coast Daily said on some routes they travelled fare evaders outnumbered paying passengers.

Transport and Main Roads Minister Mark Bailey on Friday said fare evasion and aggressive behaviour towards drivers had become a serious issue for the industry which the government would not ignore.

"It comes down to respect for others and people just doing their job," Mr Bailey said.

"From government to passengers, bus operators and unions - we can all agree: there's absolutely zero tolerance for violence against bus drivers."

One driver said he had observed what appeared to be a drug exchange go down, with the dealer - who had not paid to get on - then getting off to cross the road to catch a bus back in the other direction.

In another incident the driver could smell up to eight young people chroming an inhalant that was either hair spray or a deodorant at the back of the bus.

Others say they have found syringes on the floor after someone had obviously shot up and on other occasions have smelt pot smoke coming from the rear of their buses.

"Kids are getting away with what they want," one driver said.

"This week I saw a couple engage in near intercourse and then start arguing and swearing loudly at each other."

Reader poll

Do you feel safe travelling on Coast buses?

This poll ended on 21 November 2019.

Current Results

Yes, I've never had an issue

33%

No, I avoid catching public transport because of it

55%

Sometimes, but it's like that everywhere

11%

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The claims come as the Department of Transport and Main Roads has engaged independent market research company Kantar to survey drivers on their experiences and observations.

Researchers would also speak directly with young people and parents about factors contributing to deliberate fare evasion which had now reached a $25m cost on South East Queensland bus routes.

Mr Bailey said the government had announced a raft of measures to bolster bus driver safety including an increased presence of inspectors - known as Senior Network Officers - a TV campaigner and more safety barriers.

Eight new TransLink recruits last month started the final phase of their training before they join the south east's 49 senior network officers later this year.

"New TV ads will air in the near future featuring real-life scenarios faced on the network by drivers, with the simple message: this behaviour against bus drivers is not acceptable," Mr Bailey said.

"The Palaszczuk Government is also helping to fund new driver safety barriers and anti-shatter window for buses as part of a partnership with Caboolture Buslines.

"After last year launching a $3.93 million fund to help bus companies install driver safety barriers, more than 50 per cent of buses in Queensland will now have a driver safety barrier by June 2020."

Health Minister Steven Miles last week called on manufacturers to change their formulas to tackle the issue of chroming, and announced a roundtable with industry, retailers and clinicians to look at potential responses.

"Inhalant abuse is a complex social problem requiring support from government, industry and the community-based sector," Mr Bailey said. "This roundtable will be convened by Queensland's Chief Health Officer Dr Jeanette Young."

The Transport Workers' Union (Queensland Branch) Secretary Peter Biagini last month after discussions with the government said it welcomed its efforts to fight back against "the scourge of violence against bus drivers".

"We know that having more enforcement on the buses, as well as improving safety measures such as driver barriers, will have a tangible and positive impact on bus driver safety across Queensland," he said.

Drivers say they rarely see Senior Network Officers on their buses and then its for no more than a couple of hours.